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  1. 03 3月, 2015 3 次提交
  3. 14 2月, 2015 1 次提交
  5. 13 2月, 2015 1 次提交
  7. 28 10月, 2014 2 次提交
  9. 27 10月, 2014 3 次提交
  11. 25 9月, 2014 1 次提交
    • Z
      cpuset: PF_SPREAD_PAGE and PF_SPREAD_SLAB should be atomic flags · 2ad654bc
      由 Zefan Li 提交于 
      When we change cpuset.memory_spread_{page,slab}, cpuset will flip
PF_SPREAD_{PAGE,SLAB} bit of tsk->flags for each task in that cpuset.
This should be done using atomic bitops, but currently we don't,
which is broken.

Tetsuo reported a hard-to-reproduce kernel crash on RHEL6, which happened
when one thread tried to clear PF_USED_MATH while at the same time another
thread tried to flip PF_SPREAD_PAGE/PF_SPREAD_SLAB. They both operate on
the same task.

Here's the full report:
https://lkml.org/lkml/2014/9/19/230

To fix this, we make PF_SPREAD_PAGE and PF_SPREAD_SLAB atomic flags.

v4:
- updated mm/slab.c. (Fengguang Wu)
- updated Documentation.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Cc: Kees Cook <keescook@chromium.org>
Fixes: 950592f7 ("cpusets: update tasks' page/slab spread flags in time")
Cc: <stable@vger.kernel.org> # 2.6.31+
Reported-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NZefan Li <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      2ad654bc
  13. 19 9月, 2014 1 次提交
  15. 30 7月, 2014 1 次提交
  17. 15 7月, 2014 1 次提交
    • T
      cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes · 5577964e
      由 Tejun Heo 提交于 
      Currently, cgroup_subsys->base_cftypes is used for both the unified
default hierarchy and legacy ones and subsystems can mark each file
with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE if it has to appear
only on one of them.  This is quite hairy and error-prone.  Also, we
may end up exposing interface files to the default hierarchy without
thinking it through.

cgroup_subsys will grow two separate cftype arrays and apply each only
on the hierarchies of the matching type.  This will allow organizing
cftypes in a lot clearer way and encourage subsystems to scrutinize
the interface which is being exposed in the new default hierarchy.

In preparation, this patch renames cgroup_subsys->base_cftypes to
cgroup_subsys->legacy_cftypes.  This patch is pure rename.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NLi Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Aristeu Rozanski <aris@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      5577964e
  19. 10 7月, 2014 12 次提交
    • L
      cpuset: export effective masks to userspace · afd1a8b3
      由 Li Zefan 提交于 
      cpuset.cpus and cpuset.mems are the configured masks, and we need
to export effective masks to userspace, so users know the real
cpus_allowed and mems_allowed that apply to the tasks in a cpuset.

v2:
- export those masks unconditionally, suggested by Tejun.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      afd1a8b3
    • L
      cpuset: allow writing offlined masks to cpuset.cpus/mems · 5d8ba82c
      由 Li Zefan 提交于 
      As the configured masks won't be limited by its parent, and the top
cpuset's masks won't change when hotplug happens, it's natural to
allow writing offlined masks to the configured masks.

If on default hierarchy:

	# echo 0 > /sys/devices/system/cpu/cpu1/online
	# mkdir /cpuset/sub
	# echo 1 > /cpuset/sub/cpuset.cpus
	# cat /cpuset/sub/cpuset.cpus
	1

If on legacy hierarchy:

	# echo 0 > /sys/devices/system/cpu/cpu1/online
	# mkdir /cpuset/sub
	# echo 1 > /cpuset/sub/cpuset.cpus
	-bash: echo: write error: Invalid argument

Note the checks don't need to be gated by cgroup_on_dfl, because we've
initialized top_cpuset.{cpus,mems}_allowed accordingly in cpuset_bind().
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      5d8ba82c
    • L
      cpuset: enable onlined cpu/node in effective masks · be4c9dd7
      由 Li Zefan 提交于 
      Firstly offline cpu1:

  # echo 0-1 > cpuset.cpus
  # echo 0 > /sys/devices/system/cpu/cpu1/online
  # cat cpuset.cpus
  0-1
  # cat cpuset.effective_cpus
  0

Then online it:

  # echo 1 > /sys/devices/system/cpu/cpu1/online
  # cat cpuset.cpus
  0-1
  # cat cpuset.effective_cpus
  0-1

And cpuset will bring it back to the effective mask.

The implementation is quite straightforward. Instead of calculating the
offlined cpus/mems and do updates, we just set the new effective_mask
to online_mask & congifured_mask.

This is a behavior change for default hierarchy, so legacy hierarchy
won't be affected.

v2:
- make refactoring of cpuset_hotplug_update_tasks() as seperate patch,
  suggested by Tejun.
- make hotplug_update_tasks_insane() use @new_cpus and @new_mems as
  hotplug_update_tasks_sane() does.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      be4c9dd7
    • L
      cpuset: refactor cpuset_hotplug_update_tasks() · 390a36aa
      由 Li Zefan 提交于 
      We mix the handling for both default hierarchy and legacy hierarchy in
the same function, and it's quite messy, so split into two functions.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      390a36aa
    • L
      cpuset: make cs->{cpus, mems}_allowed as user-configured masks · 7e88291b
      由 Li Zefan 提交于 
      Now we've used effective cpumasks to enforce hierarchical manner,
we can use cs->{cpus,mems}_allowed as configured masks.

Configured masks can be changed by writing cpuset.cpus and cpuset.mems
only. The new behaviors are:

- They won't be changed by hotplug anymore.
- They won't be limited by its parent's masks.

This ia a behavior change, but won't take effect unless mount with
sane_behavior.

v2:
- Add comments to explain the differences between configured masks and
effective masks.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      7e88291b
    • L
      cpuset: apply cs->effective_{cpus,mems} · ae1c8023
      由 Li Zefan 提交于 
      Now we can use cs->effective_{cpus,mems} as effective masks. It's
used whenever:

- we update tasks' cpus_allowed/mems_allowed,
- we want to retrieve tasks_cs(tsk)'s cpus_allowed/mems_allowed.

They actually replace effective_{cpu,node}mask_cpuset().

effective_mask == configured_mask & parent effective_mask except when
the reault is empty, in which case it inherits parent effective_mask.
The result equals the mask computed from effective_{cpu,node}mask_cpuset().

This won't affect the original legacy hierarchy, because in this case we
make sure the effective masks are always the same with user-configured
masks.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      ae1c8023
    • L
      cpuset: initialize top_cpuset's configured masks at mount · 39bd0d15
      由 Li Zefan 提交于 
      We now have to support different behaviors for default hierachy and
legacy hiearchy, top_cpuset's configured masks need to be initialized
accordingly.

Suppose we've offlined cpu1.

On default hierarchy:

	# mount -t cgroup -o __DEVEL__sane_behavior xxx /cpuset
	# cat /cpuset/cpuset.cpus
	0-15

On legacy hierarchy:

	# mount -t cgroup xxx /cpuset
	# cat /cpuset/cpuset.cpus
	0,2-15
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      39bd0d15
    • L
      cpuset: use effective cpumask to build sched domains · 8b5f1c52
      由 Li Zefan 提交于 
      We're going to have separate user-configured masks and effective ones.

Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.

We calculate effective mask this way:
  - top cpuset's effective_mask == online_mask, otherwise
  - cpuset's effective_mask == configured_mask & parent effective_mask,
    if the result is empty, it inherits parent effective mask.

Those behavior changes are for default hierarchy only. For legacy
hierarchy, effective_mask and configured_mask are the same, so we won't
break old interfaces.

We should partition sched domains according to effective_cpus, which
is the real cpulist that takes effects on tasks in the cpuset.

This won't introduce behavior change.

v2:
- Add a comment for the call of rebuild_sched_domains(), suggested
by Tejun.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      8b5f1c52
    • L
      cpuset: inherit ancestor's masks if effective_{cpus, mems} becomes empty · 554b0d1c
      由 Li Zefan 提交于 
      We're going to have separate user-configured masks and effective ones.

Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.

We calculate effective mask this way:
  - top cpuset's effective_mask == online_mask, otherwise
  - cpuset's effective_mask == configured_mask & parent effective_mask,
    if the result is empty, it inherits parent effective mask.

Those behavior changes are for default hierarchy only. For legacy
hierarchy, effective_mask and configured_mask are the same, so we won't
break old interfaces.

To make cs->effective_{cpus,mems} to be effective masks, we need to
  - update the effective masks at hotplug
  - update the effective masks at config change
  - take on ancestor's mask when the effective mask is empty

The last item is done here.

This won't introduce behavior change.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      554b0d1c
    • L
      cpuset: update cs->effective_{cpus, mems} when config changes · 734d4513
      由 Li Zefan 提交于 
      We're going to have separate user-configured masks and effective ones.

Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.

We calculate effective mask this way:
  - top cpuset's effective_mask == online_mask, otherwise
  - cpuset's effective_mask == configured_mask & parent effective_mask,
    if the result is empty, it inherits parent effective mask.

Those behavior changes are for default hierarchy only. For legacy
hierarchy, effective_mask and configured_mask are the same, so we won't
break old interfaces.

To make cs->effective_{cpus,mems} to be effective masks, we need to
  - update the effective masks at hotplug
  - update the effective masks at config change
  - take on ancestor's mask when the effective mask is empty

The second item is done here. We don't need to treat root_cs specially
in update_cpumasks_hier().

This won't introduce behavior change.

v3:
- add a WARN_ON() to check if effective masks are the same with configured
  masks on legacy hierarchy.
- pass trialcs->cpus_allowed to update_cpumasks_hier() and add a comment for
  it. Similar change for update_nodemasks_hier(). Suggested by Tejun.

v2:
- revise the comment in update_{cpu,node}masks_hier(), suggested by Tejun.
- fix to use @CP instead of @cs in these two functions.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      734d4513
    • L
      cpuset: update cpuset->effective_{cpus,mems} at hotplug · 1344ab9c
      由 Li Zefan 提交于 
      We're going to have separate user-configured masks and effective ones.

Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.

We calculate effective mask this way:
  - top cpuset's effective_mask == online_mask, otherwise
  - cpuset's effective_mask == configured_mask & parent effective_mask,
    if the result is empty, it inherits parent effective mask.

Those behavior changes are for default hierarchy only. For legacy
hierarchy, effective_mask and configured_mask are the same, so we won't
break old interfaces.

To make cs->effective_{cpus,mems} to be effective masks, we need to
  - update the effective masks at hotplug
  - update the effective masks at config change
  - take on ancestor's mask when the effective mask is empty

The first item is done here.

This won't introduce behavior change.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      1344ab9c
    • L
      cpuset: add cs->effective_cpus and cs->effective_mems · e2b9a3d7
      由 Li Zefan 提交于 
      We're going to have separate user-configured masks and effective ones.

Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.

We calculate effective mask this way:
  - top cpuset's effective_mask == online_mask, otherwise
  - cpuset's effective_mask == configured_mask & parent effective_mask,
    if the result is empty, it inherits parent effective mask.

Those behavior changes are for default hierarchy only. For legacy
hierachy, effective_mask and configured_mask are the same, so we won't
break old interfaces.

This patch adds the effective masks to struct cpuset and initializes
them. The effective masks of the top cpuset is the same with configured
masks, and a child cpuset inherits its parent's effective masks.

This won't introduce behavior change.

v2:
- s/real_{mems,cpus}_allowed/effective_{mems,cpus}, suggested by Tejun.
- don't init effective masks in cpuset_css_online() if !cgroup_on_dfl.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      e2b9a3d7
  21. 09 7月, 2014 1 次提交
    • T
      cgroup: remove sane_behavior support on non-default hierarchies · aa6ec29b
      由 Tejun Heo 提交于 
      sane_behavior has been used as a development vehicle for the default
unified hierarchy.  Now that the default hierarchy is in place, the
flag became redundant and confusing as its usage is allowed on all
hierarchies.  There are gonna be either the default hierarchy or
legacy ones.  Let's make that clear by removing sane_behavior support
on non-default hierarchies.

This patch replaces cgroup_sane_behavior() with cgroup_on_dfl().  The
comment on top of CGRP_ROOT_SANE_BEHAVIOR is moved to on top of
cgroup_on_dfl() with sane_behavior specific part dropped.

On the default and legacy hierarchies w/o sane_behavior, this
shouldn't cause any behavior differences.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NLi Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
      aa6ec29b
  23. 02 7月, 2014 1 次提交
    • T
      cpuset: break kernfs active protection in cpuset_write_resmask() · 76bb5ab8
      由 Tejun Heo 提交于 
      Writing to either "cpuset.cpus" or "cpuset.mems" file flushes
cpuset_hotplug_work so that cpu or memory hotunplug doesn't end up
migrating tasks off a cpuset after new resources are added to it.

As cpuset_hotplug_work calls into cgroup core via
cgroup_transfer_tasks(), this flushing adds the dependency to cgroup
core locking from cpuset_write_resmak().  This used to be okay because
cgroup interface files were protected by a different mutex; however,
8353da1f ("cgroup: remove cgroup_tree_mutex") simplified the
cgroup core locking and this dependency became a deadlock hazard -
cgroup file removal performed under cgroup core lock tries to drain
on-going file operation which is trying to flush cpuset_hotplug_work
blocked on the same cgroup core lock.

The locking simplification was done because kernfs added an a lot
easier way to deal with circular dependencies involving kernfs active
protection.  Let's use the same strategy in cpuset and break active
protection in cpuset_write_resmask().  While it isn't the prettiest,
this is a very rare, likely unique, situation which also goes away on
the unified hierarchy.

The commands to trigger the deadlock warning without the patch and the
lockdep output follow.

 localhost:/ # mount -t cgroup -o cpuset xxx /cpuset
 localhost:/ # mkdir /cpuset/tmp
 localhost:/ # echo 1 > /cpuset/tmp/cpuset.cpus
 localhost:/ # echo 0 > cpuset/tmp/cpuset.mems
 localhost:/ # echo $$ > /cpuset/tmp/tasks
 localhost:/ # echo 0 > /sys/devices/system/cpu/cpu1/online

  ======================================================
  [ INFO: possible circular locking dependency detected ]
  3.16.0-rc1-0.1-default+ #7 Not tainted
  -------------------------------------------------------
  kworker/1:0/32649 is trying to acquire lock:
   (cgroup_mutex){+.+.+.}, at: [<ffffffff8110e3d7>] cgroup_transfer_tasks+0x37/0x150

  but task is already holding lock:
   (cpuset_hotplug_work){+.+...}, at: [<ffffffff81085412>] process_one_work+0x192/0x520

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #2 (cpuset_hotplug_work){+.+...}:
  ...
  -> #1 (s_active#175){++++.+}:
  ...
  -> #0 (cgroup_mutex){+.+.+.}:
  ...

  other info that might help us debug this:

  Chain exists of:
    cgroup_mutex --> s_active#175 --> cpuset_hotplug_work

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(cpuset_hotplug_work);
				 lock(s_active#175);
				 lock(cpuset_hotplug_work);
    lock(cgroup_mutex);

   *** DEADLOCK ***

  2 locks held by kworker/1:0/32649:
   #0:  ("events"){.+.+.+}, at: [<ffffffff81085412>] process_one_work+0x192/0x520
   #1:  (cpuset_hotplug_work){+.+...}, at: [<ffffffff81085412>] process_one_work+0x192/0x520

  stack backtrace:
  CPU: 1 PID: 32649 Comm: kworker/1:0 Not tainted 3.16.0-rc1-0.1-default+ #7
 ...
  Call Trace:
   [<ffffffff815a5f78>] dump_stack+0x72/0x8a
   [<ffffffff810c263f>] print_circular_bug+0x10f/0x120
   [<ffffffff810c481e>] check_prev_add+0x43e/0x4b0
   [<ffffffff810c4ee6>] validate_chain+0x656/0x7c0
   [<ffffffff810c53d2>] __lock_acquire+0x382/0x660
   [<ffffffff810c57a9>] lock_acquire+0xf9/0x170
   [<ffffffff815aa13f>] mutex_lock_nested+0x6f/0x380
   [<ffffffff8110e3d7>] cgroup_transfer_tasks+0x37/0x150
   [<ffffffff811129c0>] hotplug_update_tasks_insane+0x110/0x1d0
   [<ffffffff81112bbd>] cpuset_hotplug_update_tasks+0x13d/0x180
   [<ffffffff811148ec>] cpuset_hotplug_workfn+0x18c/0x630
   [<ffffffff810854d4>] process_one_work+0x254/0x520
   [<ffffffff810875dd>] worker_thread+0x13d/0x3d0
   [<ffffffff8108e0c8>] kthread+0xf8/0x100
   [<ffffffff815acaec>] ret_from_fork+0x7c/0xb0
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NLi Zefan <lizefan@huawei.com>
Tested-by: NLi Zefan <lizefan@huawei.com>
      76bb5ab8
  25. 25 6月, 2014 1 次提交
    • G
      cpuset,mempolicy: fix sleeping function called from invalid context · 391acf97
      由 Gu Zheng 提交于 
      When runing with the kernel(3.15-rc7+), the follow bug occurs:
[ 9969.258987] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:586
[ 9969.359906] in_atomic(): 1, irqs_disabled(): 0, pid: 160655, name: python
[ 9969.441175] INFO: lockdep is turned off.
[ 9969.488184] CPU: 26 PID: 160655 Comm: python Tainted: G       A      3.15.0-rc7+ #85
[ 9969.581032] Hardware name: FUJITSU-SV PRIMEQUEST 1800E/SB, BIOS PRIMEQUEST 1000 Series BIOS Version 1.39 11/16/2012
[ 9969.706052]  ffffffff81a20e60 ffff8803e941fbd0 ffffffff8162f523 ffff8803e941fd18
[ 9969.795323]  ffff8803e941fbe0 ffffffff8109995a ffff8803e941fc58 ffffffff81633e6c
[ 9969.884710]  ffffffff811ba5dc ffff880405c6b480 ffff88041fdd90a0 0000000000002000
[ 9969.974071] Call Trace:
[ 9970.003403]  [<ffffffff8162f523>] dump_stack+0x4d/0x66
[ 9970.065074]  [<ffffffff8109995a>] __might_sleep+0xfa/0x130
[ 9970.130743]  [<ffffffff81633e6c>] mutex_lock_nested+0x3c/0x4f0
[ 9970.200638]  [<ffffffff811ba5dc>] ? kmem_cache_alloc+0x1bc/0x210
[ 9970.272610]  [<ffffffff81105807>] cpuset_mems_allowed+0x27/0x140
[ 9970.344584]  [<ffffffff811b1303>] ? __mpol_dup+0x63/0x150
[ 9970.409282]  [<ffffffff811b1385>] __mpol_dup+0xe5/0x150
[ 9970.471897]  [<ffffffff811b1303>] ? __mpol_dup+0x63/0x150
[ 9970.536585]  [<ffffffff81068c86>] ? copy_process.part.23+0x606/0x1d40
[ 9970.613763]  [<ffffffff810bf28d>] ? trace_hardirqs_on+0xd/0x10
[ 9970.683660]  [<ffffffff810ddddf>] ? monotonic_to_bootbased+0x2f/0x50
[ 9970.759795]  [<ffffffff81068cf0>] copy_process.part.23+0x670/0x1d40
[ 9970.834885]  [<ffffffff8106a598>] do_fork+0xd8/0x380
[ 9970.894375]  [<ffffffff81110e4c>] ? __audit_syscall_entry+0x9c/0xf0
[ 9970.969470]  [<ffffffff8106a8c6>] SyS_clone+0x16/0x20
[ 9971.030011]  [<ffffffff81642009>] stub_clone+0x69/0x90
[ 9971.091573]  [<ffffffff81641c29>] ? system_call_fastpath+0x16/0x1b

The cause is that cpuset_mems_allowed() try to take
mutex_lock(&callback_mutex) under the rcu_read_lock(which was hold in
__mpol_dup()). And in cpuset_mems_allowed(), the access to cpuset is
under rcu_read_lock, so in __mpol_dup, we can reduce the rcu_read_lock
protection region to protect the access to cpuset only in
current_cpuset_is_being_rebound(). So that we can avoid this bug.

This patch is a temporary solution that just addresses the bug
mentioned above, can not fix the long-standing issue about cpuset.mems
rebinding on fork():

"When the forker's task_struct is duplicated (which includes
 ->mems_allowed) and it races with an update to cpuset_being_rebound
 in update_tasks_nodemask() then the task's mems_allowed doesn't get
 updated. And the child task's mems_allowed can be wrong if the
 cpuset's nodemask changes before the child has been added to the
 cgroup's tasklist."
Signed-off-by: NGu Zheng <guz.fnst@cn.fujitsu.com>
Acked-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: stable <stable@vger.kernel.org>
      391acf97
  27. 05 6月, 2014 1 次提交
  29. 17 5月, 2014 1 次提交
    • T
      cgroup: remove css_parent() · 5c9d535b
      由 Tejun Heo 提交于 
      cgroup in general is moving towards using cgroup_subsys_state as the
fundamental structural component and css_parent() was introduced to
convert from using cgroup->parent to css->parent.  It was quite some
time ago and we're moving forward with making css more prominent.

This patch drops the trivial wrapper css_parent() and let the users
dereference css->parent.  While at it, explicitly mark fields of css
which are public and immutable.

v2: New usage from device_cgroup.c converted.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: N"David S. Miller" <davem@davemloft.net>
Acked-by: NLi Zefan <lizefan@huawei.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Johannes Weiner <hannes@cmpxchg.org>
      5c9d535b
  31. 14 5月, 2014 2 次提交
    • T
      cgroup: replace cftype->write_string() with cftype->write() · 451af504
      由 Tejun Heo 提交于 
      Convert all cftype->write_string() users to the new cftype->write()
which maps directly to kernfs write operation and has full access to
kernfs and cgroup contexts.  The conversions are mostly mechanical.

* @css and @cft are accessed using of_css() and of_cft() accessors
  respectively instead of being specified as arguments.

* Should return @nbytes on success instead of 0.

* @buf is not trimmed automatically.  Trim if necessary.  Note that
  blkcg and netprio don't need this as the parsers already handle
  whitespaces.

cftype->write_string() has no user left after the conversions and
removed.

While at it, remove unnecessary local variable @p in
cgroup_subtree_control_write() and stale comment about
CGROUP_LOCAL_BUFFER_SIZE in cgroup_freezer.c.

This patch doesn't introduce any visible behavior changes.

v2: netprio was missing from conversion.  Converted.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NAristeu Rozanski <arozansk@redhat.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NLi Zefan <lizefan@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
      451af504
    • T
      cgroup: rename css_tryget*() to css_tryget_online*() · ec903c0c
      由 Tejun Heo 提交于 
      Unlike the more usual refcnting, what css_tryget() provides is the
distinction between online and offline csses instead of protection
against upping a refcnt which already reached zero.  cgroup is
planning to provide actual tryget which fails if the refcnt already
reached zero.  Let's rename the existing trygets so that they clearly
indicate that they're onliness.

I thought about keeping the existing names as-are and introducing new
names for the planned actual tryget; however, given that each
controller participates in the synchronization of the online state, it
seems worthwhile to make it explicit that these functions are about
on/offline state.

Rename css_tryget() to css_tryget_online() and css_tryget_from_dir()
to css_tryget_online_from_dir().  This is pure rename.

v2: cgroup_freezer grew new usages of css_tryget().  Update
    accordingly.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Acked-by: NLi Zefan <lizefan@huawei.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
      ec903c0c
  33. 06 5月, 2014 2 次提交
  35. 04 4月, 2014 1 次提交
  37. 19 3月, 2014 1 次提交
    • T
      cgroup: drop const from @buffer of cftype->write_string() · 4d3bb511
      由 Tejun Heo 提交于 
      cftype->write_string() just passes on the writeable buffer from kernfs
and there's no reason to add const restriction on the buffer.  The
only thing const achieves is unnecessarily complicating parsing of the
buffer.  Drop const from @buffer.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NLi Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>                                           
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      4d3bb511
  39. 04 3月, 2014 1 次提交
  41. 27 2月, 2014 2 次提交
    • L
      cpuset: fix a race condition in __cpuset_node_allowed_softwall() · 99afb0fd
      由 Li Zefan 提交于 
      It's not safe to access task's cpuset after releasing task_lock().
Holding callback_mutex won't help.

Cc: <stable@vger.kernel.org>
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      99afb0fd
    • L
      cpuset: fix a locking issue in cpuset_migrate_mm() · 47295830
      由 Li Zefan 提交于 
      I can trigger a lockdep warning:

  # mount -t cgroup -o cpuset xxx /cgroup
  # mkdir /cgroup/cpuset
  # mkdir /cgroup/tmp
  # echo 0 > /cgroup/tmp/cpuset.cpus
  # echo 0 > /cgroup/tmp/cpuset.mems
  # echo 1 > /cgroup/tmp/cpuset.memory_migrate
  # echo $$ > /cgroup/tmp/tasks
  # echo 1 > /cgruop/tmp/cpuset.mems

  ===============================
  [ INFO: suspicious RCU usage. ]
  3.14.0-rc1-0.1-default+ #32 Not tainted
  -------------------------------
  include/linux/cgroup.h:682 suspicious rcu_dereference_check() usage!
  ...
    [<ffffffff81582174>] dump_stack+0x72/0x86
    [<ffffffff810b8f01>] lockdep_rcu_suspicious+0x101/0x140
    [<ffffffff81105ba1>] cpuset_migrate_mm+0xb1/0xe0
  ...

We used to hold cgroup_mutex when calling cpuset_migrate_mm(), but now
we hold cpuset_mutex, which causes task_css() to complain.

This is not a false-positive but a real issue.

Holding cpuset_mutex won't prevent a task from migrating to another
cpuset, and it won't prevent the original task->cgroup from destroying
during this change.

Fixes: 5d21cc2d (cpuset: replace cgroup_mutex locking with cpuset internal locking)
Cc: <stable@vger.kernel.org> # 3.9+
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Sigend-off-by: NTejun Heo <tj@kernel.org>
      47295830